Charles Ellicott Commentary Psalms 100:3

"Know ye that Jehovah, he is God: It is he that hath made us, and we are his; We are his people, and the sheep of his pasture." — Psalms 100:3 (ASV)

And not we ourselves. — Most commentators now prefer the reading “His we are,” as keeping the parallelism better, besides having great manuscript support. The concluding part of the verse is an echo of Psalm 95:7.